<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>表格边框合并</title>
    <style>
        table{
            border-collapse: collapse;
        }
    </style>
</head>

<body>
    <table border='1'>
        <tr>
            <td>姓名</td>
            <td>性别</td>
            <td>年纪</td>
            <td>班级</td>
        </tr>
        <tr>
            <td>小明</td>
            <td>男</td>
            <td>18</td>
            <td>一年级</td>
        </tr>
        <tr>
            <td>小红</td>
            <td>女</td>
            <td>20</td>
            <td>一年级</td>
        </tr>
        <tr>
            <td>小明</td>
            <td>男</td>
            <td>18</td>
            <td>一年级</td>
        </tr>
        <tr>
            <td>小红</td>
            <td>女</td>
            <td>20</td>
            <td>一年级</td>
        </tr>
    </table>

</body>

</html>